Depending on the input parameter ObtainInfoMode, this operation may return a
sequence of the EventTypes the target object is interested in receiving.
If 'ALL_NOW_UPDATES_OFF' or 'ALL_NOW_UPDATES_ON' is given a sequence will
be returned, otherwise not. If 'ALL_NOW_UPDATES_OFF' or 'NONE_NOW_UPDATES_OFF'
are issued the target object will not inform the associated NotifySubscribe object
when an update occurs. 'ALL_NOW_UPDATES_ON' or 'NONE_NOW_UPDATES_ON' will
result in that update information will be sent.

To check if certain Quality of Service properties can be added to events in
the current context of the target object this operation should be used. If we
cannot support the required settings an exception describing why will be raised.